1. Field
The present disclosure relates generally to protection of power converters and, more specifically, to surge protection at an input of a power converter.
2. Discussion of the Related Art
Many electronic devices, such as cell phones, laptop computers, etc., use direct current (dc) power to operate. Conventional wall outlets generally deliver a high voltage alternating current (ac) power that needs to be transformed to dc power in order to be used as a power source by most electronic devices. Switched mode power converters are commonly used due to their high efficiency, small size, and low weight to convert the high voltage ac power to a regulated dc power. In operation, a controller of the switched mode power converter may provide output regulation by sensing the output of the power converter and controlling the switch in a closed loop. For example, the controller may receive a feedback signal representative of the output and then vary one of the control parameters (e.g., duty ratio or the number of ON and OFF cycles of the switch per unit time) based on the feedback signal to regulate the output to a desired quantity.
Power converters are occasionally exposed to surges in the received input voltage, which is generally referred to as an overvoltage condition. Switching of the power switch during these overvoltage conditions may damage various components within the power converter, such as the power switch. Thus, many power converters include overvoltage protection circuits to detect the overvoltage conditions and divert excess voltage in order to prevent damage to the power converter.